As the use of battery-backed-up electronic devices continues to grow at a rapid pace, manufacturers are constantly trying to improve the run-down time, or time period beginning when battery operation of a device begins until the battery can no longer supply sufficient power to operate the device. By increasing the run-down time, not only can the device operate for a longer amount of time running on battery power, but the manufacture can also use smaller, less expensive batteries for a given amount of run-down time.
One way of increasing the run-down time is to use larger batteries, as the larger a battery for a given battery type, the more charge can be stored by said battery. In addition, much research is ongoing in search of different types of batteries to provide higher and higher charge densities. While current research shows promise, improvements in batteries have been limited. Thus, another way of improving run-down time is to improve the devices themselves in order to reduce the amount of power used by the given device. Actually, this is a desirable goal regardless of the type of battery being used, because any battery, no matter how exotic, will always have a given charge density associated with it, and therefore, any improvements in device efficiency are always desirable.
Such techniques that improve, or increase, the run-down time of a device are applicable to battery usage in a device that uses batteries; such techniques are especially useful in communication devices, such as telephony over internet protocol, also referred to in the art as voice-over-IP or VoIP, because emergency service, such as 911 service, for example, must be provided during loss-of-off-site-power, or LOOP, such as occurs during a storm, for example, when power lines from local utility companies may become disconnected.
Some ways of reducing power consumption in battery power devices, as well as electrical devices powered by household current, include turning off certain portions of the device after one or more of the given portions have been idle, or unused, for a given amount of time. Thus, a timer, or similar means, may be used where the time starts to count down when current that powers a certain portion of a device falls below a threshold. Such ways are somewhat effective, in that power to a portion is shut down following a period of idle, or no, use. However, during the period until the timer instructs that power be interrupted, the controller continues to draw current, even though there is not a load drawing current from it. Furthermore, in order to sense when a load has been applied and current is needed at the output, the timer circuit continues to draw current constantly. While timer circuit current and the current drawn by the controller until shut-down may be only a few milliamps, this may make the difference in meeting an industry standard run-down time by using a larger size battery than would be required if the timer circuit did not draw current and the controller did not draw current when its output is in a no-load condition.
Thus, there is a need in the art for a method and system for immediately detecting a no-load condition at the output of the controller and shutting down power to the controller (referred to herein as sleep mode). Furthermore, there is a need in the art for the ability to ‘wake’ from sleep mode upon the need for power from a load on the converter output. Moreover, there is a need in the art for these features without the power usage by circuitry detecting when the load has been applied.